Vehicle regenerative deceleration actuator and indicator system and method

ABSTRACT

An indicator system for regenerative slowing of a hybrid or electric vehicle includes at least one deceleration indicator positioned on the rear of a vehicle, a vehicle deceleration monitor configured to monitor deceleration and produce a control output signal if deceleration exceeds a predetermined level, a vehicle braking module configured to detect application of the conventional vehicle brakes, and an indicator control module configured to actuate the deceleration indicator when a vehicle deceleration output signal exceeding the predetermined level is received and conventional vehicle brakes are not applied. An independent driver-operated regen mode switch may provide for driver-initiated regen slowing independent of the conventional vehicle brakes or gears, with the deceleration indicator being on when regen mode is initiated by the driver without application of friction brakes, and the predetermined deceleration level is exceeded.

BACKGROUND

1. Field of the Invention

The present invention generally relates to electric and hybrid vehicleswith a regeneration mode, and is particularly concerned with aregeneration mode actuator and indicator system and method for suchvehicles.

2. Related Art

Various braking systems and indicators for such systems are known forvarious types of vehicle, including traditional gas driven vehicles,hybrid vehicles, and electric vehicles. One problem with existing brakelights is that they are only turned on when the driver appliesconventional friction brakes. They are not activated when the vehicleslows down for some other reason.

An electric or hybrid vehicle automatically switches into a regenerationmode periodically as controlled by the electronic control unit (ECU)based on detected vehicle conditions, but the driver can also initiateregeneration either by applying the brakes or shifting the vehicle intolow gear. Drivers of electric or hybrid vehicles sometimes shift thevehicle into low gear to slow the vehicle while increasing efficiency bydelivering power to the storage battery of the vehicle. However, adriver following a conventional hybrid or electric vehicle which isoperating in regenerative mode without conventional brake applicationhas no indication that the vehicle is decelerating.

Some prior vehicle indicators are designed to be actuated on detectionof slowing of a vehicle resulting from either traditional frictionbraking or other types of deceleration, for example due to gearshifting. However, these systems do not discriminate between slowing asa result of applying conventional vehicle brakes and slowing for otherreasons, for example as a result of initiation of the regeneration modein a hybrid or electric vehicle.

Electric vehicles are designed to mimic the slowing that occurs ingasoline powered vehicles with an automatic transmission. In electricvehicles, the drive gear slowing sensation (referred to as leakage) andlow gear slowing (measured and speed dependent) are exclusively donewith the regenerator. In the case of low gear, the regenerator is takenclose to saturation or maximum output of the regenerator. An additionalslowing, intentional or not, reduces the kinetic recovery potential andthus the overall efficiency of the vehicle.

Driving an electric vehicle in low gear is unofficially stated as anoption by manufacturers. The problem with this mode of electric vehicleuse is that the efficiency of just coasting above leakage at all timeswhen not accelerating is continuously reduced by the slowing of lowgear, and encounters the unnecessary inefficiencies of the kineticconversion to electric power. Vehicle operators with regenerators arenot encouraged to maximize the regeneration feature with modulation ofthe brake pedal. A brake pedal that utilizes regeneration does so inconjunction with conventional braking. The operator experience isintentionally seamless. That is, the primary consideration is stoppingwith an expected vehicle slowing feedback to the operator. This offerssome kinetic recovery efficiency, but normally involves unnecessaryapplication of conventional frictional brakes.

SUMMARY OF THE INVENTION

Embodiments described herein provide for an independent driver-operatedactuator for initiation of the regeneration mode in an electric orhybrid vehicle, as well as an indicator which is actuated on detectionof regenerative-only (regen-only) slowing or deceleration of thevehicle.

In one aspect, an indicator system for regenerative slowing of a hybridor electric vehicle is provided, which comprises at least one vehiclebraking or slowing indicator positioned on the rear of a vehicle, avehicle deceleration module configured to monitor deceleration of thevehicle and provide a deceleration output signal, a vehicle brakingmodule configured to detect application of the conventional vehiclebrakes, and an indicator control module connected to the decelerationmodule and braking module and configured to actuate the vehicle slowingindicator when the vehicle deceleration exceeds a predetermined valueabove coasting and the conventional vehicle brakes are not applied. Inone embodiment, the indicator control module also monitors theregeneration status of the vehicle and actuates the slowing indicator ifthe vehicle is in the regeneration mode, the predetermined decelerationvalue is exceeded, and the conventional or friction brakes are notapplied.

According to another aspect, an independent, hand-operated regen modeactuator such as a push button or rotary switch is provided at aconvenient position in the vehicle and is linked to the existing vehicleelectronic control unit (ECU) to initiate regenerative slowing whenactuated by an operator of the vehicle. This regen mode switch may alsoprovide a signal to the indicator control module to initiatedeceleration monitoring by the deceleration module and illumination ofthe slowing indicator light when the vehicle deceleration exceeds thepredetermined value without application of the conventional vehiclebrakes. In this way, drivers following the vehicle can determine thatnotable deceleration is occurring without application of theconventional friction brakes.

The driver-operated, independent regen mode switch may be provided onthe steering wheel, the dashboard, the gear lever, or at any otherconvenient location. This provides a convenient, independent controlswitch, allowing the driver to utilize the operational efficiency of aregenerator in an electric or hybrid vehicle without having to eitherengage a low gear or press the brake pedal.

One or more deceleration indicator lights may be provided on the rear ofthe vehicle, and in one embodiment an array of two or more lights forindicating regen-only deceleration may be provided below the third brakelight on a vehicle. The deceleration indicator lights are always offwhen the brake lights are illuminated. In one embodiment, the thirdbrake light and regen-only slowing indicator may be provided in a singleunit mounted at an appropriate height in the rear center of the vehicle.

According to another aspect, a method of indicating slowing of anelectric or hybrid vehicle without application of conventional brakes isprovided, which comprises detection of deceleration of the vehicleexceeding a predetermined level when the vehicle is operating in aregeneration mode, determining whether the conventional brakes have beenapplied, actuating a deceleration indicator separate from conventionalvehicle brake lights only if the predetermined deceleration level isexceeded without application of the conventional vehicle brakes, andturning off the deceleration indicator if the conventional brakes areapplied.

In one embodiment, the deceleration indicator may also be turned off onexpiry of a predetermined time interval, and is turned on again only ifthe predetermined conditions of deceleration exceeding the predeterminedlevel without application of the conventional brakes while in theregeneration mode are still present.

This system and method provides enhanced safety by actuating a vehicleslowing indicator at the rear of an electric or hybrid vehicle in theevent of so-called regenerative braking. The system may also include anindependent regeneration control input for operation by the driver toinitiate regenerative slowing independent from operation of the vehiclebrake and gears.

Other features and advantages of the present invention will become morereadily apparent to those of ordinary skill in the art after reviewingthe following detailed description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The details of the present invention, both as to its structure andoperation, may be gleaned in part by study of the accompanying drawings,in which like reference numerals refer to like parts, and in which:

FIG. 1 is a schematic diagram illustrating one embodiment of a vehicleregenerative deceleration actuator and indicator system which controlsactuation of a regenerative braking indicator;

FIG. 2 is a perspective view of the rear of a vehicle illustrating oneembodiment of the vehicle regenerative braking or deceleration indicatorof FIG. 1;

FIG. 3 is a front elevation view illustrating the regenerative brakingindicator light array of FIG. 1 combined with an adjacent third brakelight;

FIG. 4 is a perspective view of the driver console inside a vehicleindicating options for placement of the driver-operated, independentregeneration mode actuator switch of FIG. 1;

FIG. 5 is a flow diagram illustrating the steps in one embodiment of amethod for controlling actuation of the regenerative decelerationindicator in the system of FIGS. 1 to 4;

FIG. 6 is a graph illustrating gravity or g-force versus vehicle speedin various deceleration modes; and

FIG. 7 is a flow diagram illustrating an alternative method forcontrolling actuation of the regenerative braking or decelerationindicator of FIGS. 2 and 3.

DETAILED DESCRIPTION

Certain embodiments as disclosed herein provide for a vehicleregenerative deceleration indicator system and method which may alsoincorporate a regenerative braking control button or actuator forconvenient operator control of the regenerative mode of operation of anelectric or hybrid vehicle.

After reading this description it will become apparent to one skilled inthe art how to implement the invention in various alternativeembodiments and alternative applications. However, although variousembodiments of the present invention will be described herein, it isunderstood that these embodiments are presented by way of example only,and not limitation. As such, this detailed description of variousalternative embodiments should not be construed to limit the scope orbreadth of the present invention.

FIG. 1 illustrates a first embodiment of a vehicle regenerativedeceleration or braking indicator system 50 in which an additional regenslowing or deceleration indicator or light 4 at the rear of an electricor hybrid vehicle 1 is controlled to turn on when vehicle decelerationabove a predetermined level is detected without application ofconventional friction brakes, while FIG. 5 is a flow diagramillustrating the method steps carried out by the system of FIG. 1. FIGS.2 and 3 illustrate possible locations for deceleration indicator lightor light array 4, while FIG. 4 illustrates possible locations in avehicle for an independent, driver-operated regenerative control switch7.

In the embodiment of FIGS. 1 to 5, indicator 4 is turned on if thevehicle is in the regenerative mode of operation, a predetermineddeceleration level is detected, and the conventional brakes are notapplied, i.e. the conventional brake light set 2 and 3, specificallyside brake lights 2 and the third brake light 3, are off. The regen-onlydeceleration or slowing indicator 4 may be mounted directly below thirdbrake light 3 as illustrated in FIG. 2. In one embodiment, theregenerative or “regen” deceleration indicator comprises an array ofthree indicator lights 6 mounted below the conventional third brakelight 3 in a combined light assembly or unit 8, as illustrated in FIG.3. The third brake light 3 now required by U.S. automotive safetystandards is typically located on the centerline and above the brakelights 2. Due to the variability of automotive styling betweenmanufacturers, an alternate location 5 of the third brake light 3 andregeneration light 4 combination is also shown in FIG. 2.

In one embodiment, regenerative braking indicator light 4 comprisesmultiple elements that are equal red and orange in color and reside inan array below the center high “third brake light,” offering a distinctoff red color different from the conventional red brake light 3 locatedabove light 4, with an illumination value equal to the “third brakelight.” In one embodiment, the light or lamp array 4 comprises aplurality of LEDs in a series/parallel configuration, as illustrated inFIG. 1.

In one embodiment, a regeneration mode actuator switch or control button7 is located on the steering wheel 20 or on the gear shift handle 22, asillustrated in FIG. 4, or may be located at some other convenientlocation such as on the dashboard or driver control panel, for operationby the driver in order to engage regeneration. Alternatively, twoswitches or buttons 7 may be provided at different locations. Currently,a vehicle operator of a hybrid or electric vehicle can only initiateregeneration by pressing the brake pedal or engaging electric low gear.Independent operator engagement of regenerative braking can increasevehicle efficiency, and an independently accessible control switch forinitiating regeneration in order to slow the vehicle makes suchefficiency improvements more readily accessible.

As noted above, FIG. 1 illustrates a control circuit or system 50 forcontrolling actuation of the regenerative deceleration indicator lightor lamp array 4, while FIG. 5 is a flow diagram illustrating a method ofoperation of the system of FIG. 1 to control actuation of decelerationindicator light or lamp array 4 of FIGS. 2 and 3. The method of FIG. 5is carried out by controller or microprocessor 10 of FIG. 3 based onoutput signals from regeneration module 12, brake pedal switch ordetector 13, and deceleration detection module or accelerometer 11.

The control electronics circuit of FIG. 3 includes microprocessor 10,deceleration detection module or accelerometer 11 having an output 18connected to a first input of microprocessor 10, regeneration module 12having an output 24 connected to a second input of microprocessor 10,and brake pedal detection module or switch 13 having an output 25connected to a third input of microprocessor 10. Microprocessor 10 hasan output 26 connected to deceleration indicator module 15 includingdeceleration indicator 4 via power MOSFET 14, which is rated to thecurrent and voltage requirements of the deceleration indicator or lamparray 4. A voltage regulator 9 of sufficient electrical current carryingcapacity to reduce the vehicle battery voltage to the operating level ofthe electronic components is connected between the vehicle battery andthe power input VCC of microprocessor 10.

The core of the circuit is a microprocessor 10 with a minimumrequirement of two digital inputs, one analog input with analog todigital converter with a resolution of at least ten bits, and onedigital output. The microprocessor is programmed by software, hardware,or both hardware and software to execute the control method of FIG. 5,as described in more detail below. In one embodiment, the decelerationdetection module comprises a solid state MEMS accelerometer 11 designedto sense up to 1 G with analog output 18 connected to the microprocessoranalog input via a low pass filter so as to match the input range of themicroprocessor. The accelerometer 11, microprocessor 10, voltageregulator 9, and MOSFET 14 may all be provided in one control unit orbox 16 mounted at a suitable location in the vehicle and connected viawiring as indicated in FIG. 3 to the regeneration switch module 12, thebrake pedal detection or switch module 13, and the decelerationindicator module 15 or deceleration light assembly 4.

The regeneration module is responsive to operator closing of controlbutton or switch 7 to provide output 24 connected to the secondmicroprocessor input, and an output 28 connected to the vehicleelectronic control unit (ECU) for initiation of the regeneration mode.In one embodiment, driver-operated control switch 7 is a double pole,single throw switch as illustrated in FIG. 1, but other switches may beused in alternative embodiments.

Brake pedal detection module 13 comprises a brake pedal switch 29positioned to detect application of the vehicle's conventional frictionbrakes, for example by detecting depression of the brake pedal, but anysuitable device for detecting conventional brake actuation may beprovided in alternative embodiments.

In one embodiment, deceleration indicator module 15 comprises aplurality of light emitting diodes in series/parallel configuration andlocated in the vehicle rear indicator deceleration light assembly 4 ofFIGS. 2 and 3. In this embodiment, the light array 4 comprises threesets of three diodes connected in series (D1, D2, D3; D4, D5, D6; andD7, D8, D9) and the three sets of diodes are connected in parallel.

As noted above, FIG. 5 illustrates the program steps carried out bymicroprocessor 10 based on inputs from the various detector modules.Upon program initiation or start 30, the microprocessor has a defaultcondition in which the regen deceleration indicator 4 is OFF. Theprogram polls the driver-operated regeneration mode actuator switch 7for a qualifying state (step 32). If initiation of regeneration mode viaswitch 7 is not detected, the program returns to start/indicator off(34). If a regeneration state is detected, the program polls the statusof the brake light or brake pedal switch 29 in step 35. If the brakepedal switch is closed, i.e. the brake light is ON, then regendeceleration indicator 4 remains OFF (36) and the program returns tostart (38). If the brake light set 2 and 3 are not on, which is thequalified state, the accelerometer is queried in step 40. The qualifyingstate of the accelerometer 11 is a reading greater than a predeterminedG force or G_(MAX). If less than the qualifying force, the regenerationlight or lamp assembly remains OFF and the program returns to the start(34). Once the threshold is reached, the indicator is switched ON (step42). The regeneration light assembly or indicator 4 remains on for apredetermined time period T1. After expiry of the predetermined timeperiod (44), the deceleration indicator is turned OFF (45) and thesystem recycles back to the start (step 38).

The system recycles through the steps of FIG. 5 and continues to pollthe state of the inputs, turning the regen deceleration indicator ONagain if all qualifying conditions are met. If a disqualifying state isdetected, for example either a return to the non-regeneration mode ofthe vehicle or application of the brake pedal, the deceleration lightassembly or indicator 4 is returned to OFF or remains OFF (step 34 or36). The system recycles and repeats the process until the nextqualifying event. The system incorporates a watchdog timer, errorcorrection and safety overrides. In the event of the programinadvertently stopping for a period of 1 second, the program resets,indicator 4 defaults to OFF, and the system returns to normal operation.To prevent erroneous disturbing indications with erratic multiple inputs(4 inputs in 8 seconds) outside of the normal operating envelope, theprogram goes to a timeout and inhibits the regen deceleration indicatoror light assembly 4 from returning to ON for a certain time period, forexample 20 seconds, then returns to start.

The threshold point for activation of the deceleration indicator 4 inone embodiment was a G_(MAX) of 0.07 G, but different values may be usedin other embodiments. The ON period T1 for the regen decelerationindicator or light assembly 4 was six seconds in one embodiment, but maybe a longer or shorter time period in other embodiments or for differentvehicles. The indicator light 4 therefore flashes on and off while thesystem is in the qualifying state of detected deceleration of greaterthan G_(MAX) while the conventional brakes are OFF.

The selected threshold point G_(MAX) of 0.07 G in the above embodimentwas determined through experimentation, and the results are depicted inthe graph of FIG. 6. An electric vehicle was equipped with anaccelerometer identical to accelerometer 11 of FIG. 1 and a recordingdevice, and was driven through a test area of representative roadconditions. The graph is a summery display of the G forces measuredduring various operating modes and speeds, specifically while coasting,while in regenerative operation mode, with application of theconventional friction brakes, and under hard braking conditions usingconventional brakes. The testing was conducted to determine thethreshold point where efficiency can be gained based upon recordedconditions of a vehicle equipped with a regenerator. The dotted line(COAST) in FIG. 6 illustrates typical G level while coasting. Themeasured force while the vehicle was coasting was consistently 0.02 G atall speeds above 5 MPH. Regenerative braking was measured through aseries of progressive speeds simulating average driving conditions. Theforce measured was between 0.08 G at 10 MPH to 0.12 G at 60 MPH with anaverage measurement of 0.1 G. Conventional friction braking was alsomeasured through a series of progressive speeds simulating averagedriving conditions. The force measured was between 0.15 G and 0.20 Gwhen the brakes were applied and the brake lights were illuminated. Thevehicle was put through a hard brake maneuver to define the limits ofthe braking force to determine the measurement range. Maximum brakingforce did not exceed 0.4 G above 30 MPH. The force measured graduallyreduced to 0 below 10 MPH. The conclusion of the testing resulted inselection of an optimal threshold point to illuminate the indicator,specifically around 0.07 G, corresponding to a deceleration level abovecoasting, as illustrated by the solid horizontal line in FIG. 6.

In the foregoing embodiment, the regenerative braking or decelerationindicator 4 is a regeneration-only indicator, since it is only ON whenthe vehicle slows as a result of regenerative braking withoutapplication of conventional brakes. The regeneration-only indicatorlights at the rear of the vehicle are turned ON only when a decelerationabove G_(MAX) is detected when the vehicle is in a regen mode and theconventional vehicle brakes are not applied. The braking indicator orlight array 4 may be controlled to flash on and off, as described above,or may stay on until the regenerative braking conditions are no longerdetected in alternative embodiments. The above embodiment is designedfor a vehicle which has a convenient, driver-operated regenerative modecontrol switch 7 for actuation by the driver or operator.

In an alternative embodiment, regenerative braking may be detectedsimply by detection of a deceleration above a predetermined G force orG_(MAX) without detection of application of the conventional vehiclebrakes, for example as illustrated in the flow diagram of FIG. 7. Thisalternative embodiment may be used for an electric or hybrid vehiclewhich has a driver-operated regen mode switch or control button 7, orfor a vehicle which does not have such a switch 7 and only allowsoperator initiation of regen mode by engaging a lower gear or bypressing the brake pedal.

In the embodiment of FIG. 7, the output 24 from regeneration detectionmodule 12 to the microprocessor 10 in FIG. 1 is eliminated, and the onlycontrol inputs to the microprocessor are the output 25 from brake pedalswitch 29 and the output of deceleration detection module oraccelerometer 11. The system is otherwise identical to that of FIG. 1.The separate regeneration switch 7 and module 12 of FIG. 1 may beeliminated altogether in an alternative embodiment.

In this system, after startup of the engine (step 51), the detectedG-force output of accelerometer 11 is monitored (step 52). If thedetected G force is less than G_(MAX) at step 54, the system returns tomonitoring the accelerometer. If a G force of greater than G_(MAX)(which may be 0.07 G as in the previous embodiment) is detected, thebrake pedal switch is monitored (step 55), and if the conventional brakepedal is applied and brake light 3 is on, the system returns to start(step 50) and the monitoring continues. If no application of theconventional brake pedal is detected at step 55, the decelerationindicator or light assembly 4 is turned ON (step 56), and remains onuntil time T1 expires (step 58), after which the light assembly 4 isturned OFF (step 60). The system returns to the start position and themonitoring process described above repeats.

The deceleration detector in the above embodiments comprises anelectronic inertial vehicle change of velocity detection device oraccelerometer. In one embodiment, the accelerometer is a solid statedevice that has 0.01 G sensitivity, offers resilience to unwantedvibration, and is not susceptible to mechanical deterioration. The solidstate accelerometer offers a greater degree of sensing precision that isindependent of roadway/engine off axis vibrations and deterioration of amechanical measuring mechanism.

The regeneration-only actuation method provided by the manual (operatorbutton) input 7 to engage the regenerator, as described above, allowsfor more efficient use of the vehicle's regenerator by adding anindependent access circuit and device for the vehicle operator to easilyengage the energy recovery mechanism (regenerator) as a slowing device.This new vehicle driving device is at the operator's disposal forslowing the vehicle without using conventional braking. An operator thatbecomes familiar with the new regeneration actuator or control buttoncan modify their driving pattern to increase vehicle operatingefficiency, and may quickly learn the regenerative slowing capability ofthe vehicle, and intuitively develop an understanding of how to safelyrecover momentum while converting kinetic energy to electrical energy.This may extend the range of an all-electric driven vehicle. A drivermay learn how to use the regeneration only mode switch to capture energyrelatively easily, and can adjust their driving style accordingly. Thevehicle operator can choose whether or not to use the new regenerationmode control button to initiate energy savings and safely operate thevehicle, while motorists following the vehicle are alerted to theregen-only slowing condition. If the new driver-operated control switchis inadvertently used, motorists following the vehicle still receive anindication of slowing, and the slowing does not compromise operatorcontrol.

The control system in the above embodiments uses an accelerometer withprogrammed reviews of inertial measurements and brake status to qualifyand turn on the regeneration-only deceleration indicator light, and alsocontrols the illumination time as well as inhibiting unwantedactivations.

The safety logic that prevailed with the advent of the “third brakelight” is the same logic used here, to insure that motorists are awareas soon as possible when the vehicle is decelerating. Operation of theregeneration-only slowing indicator is based on a decision matrix thattakes several vehicle operational factors into consideration todetermine that a notable deceleration event is in progress that is notthe result of conventional friction braking. The regeneration-onlydeceleration or vehicle slowing indicator 4 illuminates when adeceleration threshold above coasting occurs, which is an event thatmotorists following the vehicle should be aware of. Theregeneration-only indicator is turned off when the vehicle brakes areapplied, and it is easy for motorists to distinguish betweenregenerative and conventional braking conditions. The regeneration onlyindicator is intuitively interpreted by motorist as some sort of speedreduction indication due to the location below the third brake lightwith illumination intensity equal to that of the brake lights. Theregenerative slowing indicator 4 is off when the brakes are on so thatthere is no confusion with the familiar brake light, and what that lightimplies.

Currently, there is no indicator at the rear of a hybrid or electricvehicle to notify following vehicles that the vehicle is slowing as aresult of regenerative braking. The foregoing embodiments thereforeenhance roadway safety with the addition of an indicator separate fromthe conventional brake lights to indicate a brake-like slowing of avehicle as a result of switching into regeneration mode. The systemdescribed above may be retrofitted easily on any vehicle equipped with akinetic regenerator that can be independently initiated by the operatorfor the purpose of efficient power generating as well as slowing of thevehicle.

The embodiments described above allow a significant (empiricallymeasured) efficiency to be leveraged from electric cars and others withregenerators by means of regeneration-only action which is convenientlyand independently accessed by an operator controlled regeneration modecontrol switch 7 as described above, such as a readily accessible on-offbutton, rotary wheel, or the like mounted on the steering wheel, shiftlever, or any other driver-accessible location, or in more than one suchlocation. This allows a simple hand motion to offer operator initiatedregeneration-only for roadway slowing while the button is depressed,rather than from operation of the brake pedal or engaging low gear.Conventional brakes can be utilized if increased efficiency is notdesired, without a deterioration of operational safety.

Inclusion of an operator initiated regenerator-only slowing as well as aregeneration-only slowing indicator may be provided in electric orhybrid electric vehicles, or in a gasoline engine vehicle where aregenerator is utilized in place of an alternator driven by the gasolineengine. By isolating regenerative slowing from conventional braking witha brake pedal, an operator may simply maximize kinetic regenerationwithout generating heat from conventional friction braking.

Those of skill will appreciate that the various illustrative logicalblocks, modules, circuits, and algorithm steps described in connectionwith the embodiments disclosed herein can often be implemented aselectronic hardware, computer software, or combinations of both. Toclearly illustrate this interchangeability of hardware and software,various illustrative components, blocks, modules, circuits, and stepshave been described above generally in terms of their functionality.Whether such functionality is implemented as hardware or softwaredepends upon the particular application and design constraints imposedon the overall system. Skilled persons can implement the describedfunctionality in varying ways for each particular application, but suchimplementation decisions should not be interpreted as causing adeparture from the scope of the invention. In addition, the grouping offunctions within a module, block or step is for ease of description.Specific functions or steps can be moved from one module or blockwithout departing from the invention.

The various illustrative logical blocks and modules described inconnection with the embodiments disclosed herein can be implemented orperformed with a general purpose processor, a digital signal processor(DSP), an application specific integrated circuit (ASIC), a fieldprogrammable gate array (FPGA) or other programmable logic device,discrete gate or transistor logic, discrete hardware components, or anycombination thereof designed to perform the functions described herein.A general-purpose processor can be a microprocessor, but in thealternative, the processor can be any processor, controller,microcontroller, or state machine. A processor can also be implementedas a combination of computing devices, for example, a combination of aDSP and a microprocessor, a plurality of microprocessors, one or moremicroprocessors in conjunction with a DSP core, or any other suchconfiguration.

The steps of a method or algorithm described in connection with theembodiments disclosed herein can be embodied directly in hardware, in asoftware module executed by a processor, or in a combination of the two.A software module can reside in RAM memory, flash memory, ROM memory,EPROM memory, EEPROM memory, registers, hard disk, a removable disk, aCD-ROM, or any other form of storage medium. An exemplary storage mediumcan be coupled to the processor such that the processor can readinformation from, and write information to, the storage medium. In thealternative, the storage medium can be integral to the processor. Theprocessor and the storage medium can reside in an ASIC.

Various embodiments may also be implemented primarily in hardware using,for example, components such as application specific integrated circuits(“ASICs”), or field programmable gate arrays (“FPGAs”). Implementationof a hardware state machine capable of performing the functionsdescribed herein will also be apparent to those skilled in the relevantart. Various embodiments may also be implemented using a combination ofboth hardware and software.

The above description of the disclosed embodiments is provided to enableany person skilled in the art to make or use the invention. Variousmodifications to these embodiments will be readily apparent to thoseskilled in the art, and the generic principles described herein can beapplied to other embodiments without departing from the spirit or scopeof the invention. Thus, it is to be understood that the description anddrawings presented herein represent a presently preferred embodiment ofthe invention and are therefore representative of the subject matterwhich is broadly contemplated by the present invention. It is furtherunderstood that the scope of the present invention fully encompassesother embodiments that may become obvious to those skilled in the artand that the scope of the present invention is accordingly limited bynothing other than the appended claims.

The invention claimed is:
 1. A driver-operated vehicle regenerative(regen) deceleration actuator system, the system comprising: adriver-operated regeneration mode actuator device configured formounting in a vehicle at a location accessible by a driver, thedriver-operated regeneration mode actuator device having at least oneoutput lead configured for connection to an electronic control unit(ECU) of the vehicle to initiate regenerative slowing of the vehicle;and an indicator control module having a first input connected to thedriver-operated regeneration mode actuator device and configured to turnON a vehicle slowing indicator light at the rear of the vehicle ondetection of predetermined regen-only slowing conditions, thepredetermined regen-only slowing conditions comprising at least driverinitiation of a regeneration mode using the driver-operated regenerationmode actuator device without application of conventional friction brakesof the vehicle.
 2. The system of claim 1, further comprising a vehicledeceleration detection module configured to monitor deceleration of thevehicle, the vehicle deceleration detection module having an outputcomprising a detected deceleration G-force output signal, the indicatorcontrol module having a second input connected to the output of thevehicle deceleration detection module, and being configured to actuatethe vehicle slowing indicator light when the driver-operatedregeneration mode actuator device is actuated to initiate a regenerationmode and predetermined regen-only slowing conditions are detected, thepredetermined regen-only slowing conditions further comprising at leasta detected deceleration G-force at the second input greater thanG_(MAX), wherein G_(MAX) is a predetermined maximum G-force which isgreater than a vehicle coasting G-force corresponding to coasting of thevehicle.
 3. The system of claim 2, further comprising a vehicle brakingmodule configured to detect application of the conventional frictionbrakes of the vehicle and having a third output, the indicator controlmodule having a third input connected to the third output, wherein theindicator control module is further configured to turn ON the vehicleslowing indicator light if the vehicle is in the regeneration mode whenthe detected deceleration G-force output signal exceeds G_(MAX), and theconventional friction brakes of the vehicle are not applied.
 4. Thesystem of claim 2, wherein G_(MAX) is in the range from 0.05 to 0.1 G.5. The system of claim 4, wherein G_(MAX) is 0.07 G.
 6. The system ofclaim 2, wherein the vehicle deceleration detection module comprises anaccelerometer configured to sense deceleration levels up to at least 1G.
 7. The system of claim 6, wherein the accelerometer is a solid statedevice having at least 0.01 G sensitivity.
 8. The system of claim 1,wherein the indicator control module includes a timer and is configuredto cycle the vehicle slowing indicator light ON and OFF at predeterminedtime intervals while the predetermined regen-only slowing conditions arepresent.
 9. The system of claim 8, wherein the vehicle slowing indicatorlight is ON for a predetermined time period no greater than six secondswhile the predetermined regen-only slowing conditions are present. 10.The system of claim 1, wherein the driver-operated regeneration modeactuator device comprises a hand-operated ON-OFF switch mounted in thevehicle at a location selected from the group consisting of the steeringwheel, the gear lever, and the driver control panel, whereby a drivercan initiate regenerative slowing of the vehicle independently fromother systems of the vehicle.
 11. A method of initiating regenerative(regen-only) slowing of an electric or hybrid vehicle withoutapplication of the conventional vehicle friction brakes of the vehicle,comprising: monitoring an output of a driver-operated regeneration modeactuator switch located at a driver accessible position in an electricor hybrid vehicle; and turning ON a vehicle slowing indicator on therear of the electric or hybrid vehicle if the driver-operatedregeneration mode actuator switch is actuated and a detected vehicledeceleration exceeds a predetermined G-force of G_(MAX) which is greaterthan a vehicle coasting G-force without application of the conventionalvehicle friction brakes.
 12. The method of claim 11, further comprisingturning OFF the vehicle slowing indicator after expiry of apredetermined time interval, continuing to monitor for vehicledeceleration greater than G_(MAX) while the vehicle is operating in aregeneration mode, turning ON the vehicle slowing indicator again ifG_(MAX) is exceeded, and repeating the cycle of turning the vehicleslowing indicator ON and OFF repeatedly while the detected vehicledeceleration is greater than G_(MAX) and the conventional brakes are notapplied.
 13. The method of claim 11, wherein G_(MAX) is in the rangefrom 0.05 to 0.1 G.
 14. The method of claim 13 wherein G_(MAX) is 0.07G.
 15. A driver-operated vehicle regenerative (regen) decelerationactuator system, the system comprising: a driver-operated regenerationmode actuator switch configured for mounting in an electric or hybridvehicle at a location accessible by a driver seated in a driver seat ofthe electric or hybrid vehicle, the driver-operated regeneration modeactuator switch having at least one output lead connected to anelectronic control unit (ECU) of the vehicle to initiate regenerativeslowing of the vehicle; at least one vehicle slowing or brakingindicator configured for mounting on the rear of the electric or hybridvehicle; and an indicator control module connected to thedriver-operated regeneration mode actuator switch, and being configuredto turn ON the vehicle slowing or braking indicator at least ondetection of predetermined regen-only conditions, the predeterminedregen-only conditions comprising at least driver initiation of aregeneration mode using the driver-operated regeneration mode actuatorswitch.
 16. The system of claim 15, further comprising a vehicledeceleration detection module configured to monitor deceleration of thevehicle, the vehicle deceleration detection module having a detecteddeceleration output signal connected to an input of the indicatorcontrol module; wherein the predetermined regen-only conditions forturning ON the vehicle slowing or braking indicator further comprise adeceleration G-force greater than G_(MAX), where G_(MAX) is apredetermined maximum G-force greater than a coasting G-force of thevehicle, the coasting G-force corresponding to coasting of the vehicle.17. The system of claim 16, wherein the indicator control module isconfigured to turn OFF the vehicle slowing or braking indicator at leaston detection of any one of turning OFF of the driver-operatedregeneration mode actuator switch and a deceleration G-force less thanG_(MAX).
 18. The system of claim 16, further comprising a conventionalvehicle braking indicator separate from the vehicle slowing or brakingindicator.
 19. The system of claim 15, wherein the predeterminedregen-only conditions further comprise driver initiation of theregeneration mode using the driver-operated regeneration mode actuatorswitch when conventional brakes of the electric or hybrid vehicle arenot applied.